var base64map = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
var Crypto = {}
var util = Crypto.util = {
  // Bit-wise rotate left
  rotl: function (n, b) {
    return (n << b) | (n >>> (32 - b))
  },
  // Bit-wise rotate right
  rotr: function (n, b) {
    return (n << (32 - b)) | (n >>> b)
  },
  // Swap big-endian to little-endian and vice versa
  endian: function (n) {
    // If number given, swap endian
    if (n.constructor === Number) {
      return util.rotl(n, 8) & 0x00FF00FF |
        util.rotl(n, 24) & 0xFF00FF00
    }
    // Else, assume array and swap all items
    for (var i = 0; i < n.length; i++) {
      n[i] = util.endian(n[i])
    }
    return n
  },
  // Generate an array of any length of random bytes
  randomBytes: function (n) {
    for (var bytes = []; n > 0; n--) {
      bytes.push(Math.floor(Math.random() * 256))
    }
    return bytes
  },
  // Convert a string to a byte array
  stringToBytes: function (str) {
    var bytes = []
    for (var i = 0; i < str.length; i++) {
      bytes.push(str.charCodeAt(i))
    }
    return bytes
  },
  // Convert a byte array to a string
  bytesToString: function (bytes) {
    var str = []
    for (var i = 0; i < bytes.length; i++) {
      str.push(String.fromCharCode(bytes[i]))
    }
    return str.join('')
  },
  // Convert a string to big-endian 32-bit words
  stringToWords: function (str) {
    var words = []
    for (var c = 0, b = 0; c < str.length; c++, b += 8) {
      words[b >>> 5] |= str.charCodeAt(c) << (24 - b % 32)
    }
    return words
  },
  // Convert a byte array to big-endian 32-bits words
  bytesToWords: function (bytes) {
    var words = []
    for (var i = 0, b = 0; i < bytes.length; i++, b += 8) {
      words[b >>> 5] |= bytes[i] << (24 - b % 32)
    }
    return words
  },
  // Convert big-endian 32-bit words to a byte array
  wordsToBytes: function (words) {
    var bytes = []
    for (var b = 0; b < words.length * 32; b += 8) {
      bytes.push((words[b >>> 5] >>> (24 - b % 32)) & 0xFF)
    }
    return bytes
  },
  // Convert a byte array to a hex string
  bytesToHex: function (bytes) {
    var hex = []
    for (var i = 0; i < bytes.length; i++) {
      hex.push((bytes[i] >>> 4).toString(16))
      hex.push((bytes[i] & 0xF).toString(16))
    }
    return hex.join('')
  },
  // Convert a hex string to a byte array
  hexToBytes: function (hex) {
    var bytes = []
    for (var c = 0; c < hex.length; c += 2) {
      bytes.push(parseInt(hex.substr(c, 2), 16))
    }
    return bytes
  },
  // Convert a byte array to a base-64 string
  bytesToBase64: function (bytes) {
    // Use browser-native function if it exists
    if (typeof btoa === 'function') return btoa(util.bytesToString(bytes))
    var base64 = []
    var overflow
    for (var i = 0; i < bytes.length; i++) {
      switch (i % 3) {
        case 0:
          base64.push(base64map.charAt(bytes[i] >>> 2))
          overflow = (bytes[i] & 0x3) << 4
          break
        case 1:
          base64.push(base64map.charAt(overflow | (bytes[i] >>> 4)))
          overflow = (bytes[i] & 0xF) << 2
          break
        case 2:
          base64.push(base64map.charAt(overflow | (bytes[i] >>> 6)))
          base64.push(base64map.charAt(bytes[i] & 0x3F))
          overflow = -1
      }
    }
    // Encode overflow bits, if there are any
    if (overflow !== undefined && overflow !== -1) {
      base64.push(base64map.charAt(overflow))
    }
    // Add padding
    while (base64.length % 4 !== 0) base64.push('=')
    return base64.join('')
  },
  // Convert a base-64 string to a byte array
  base64ToBytes: function (base64) {
    // Use browser-native function if it exists
    if (typeof atob === 'function') return util.stringToBytes(atob(base64))
    // Remove non-base-64 characters
    base64 = base64.replace(/[^A-Z0-9+/]/ig, '')
    var bytes = []
    for (var i = 0; i < base64.length; i++) {
      switch (i % 4) {
        case 1:
          bytes.push((base64map.indexOf(base64.charAt(i - 1)) << 2) |
            (base64map.indexOf(base64.charAt(i)) >>> 4))
          break
        case 2:
          bytes.push(((base64map.indexOf(base64.charAt(i - 1)) & 0xF) << 4) |
            (base64map.indexOf(base64.charAt(i)) >>> 2))
          break
        case 3:
          bytes.push(((base64map.indexOf(base64.charAt(i - 1)) & 0x3) << 6) |
            (base64map.indexOf(base64.charAt(i))))
          break
      }
    }
    return bytes
  }
}

Crypto.HMAC = function (hasher, message, key, options) {
  key = key.length > hasher._blocksize * 4 ? hasher(key, { asBytes: true }) : util.stringToBytes(key)
  // XOR keys with pad constants
  var okey = key
  var ikey = key.slice(0)
  for (var i = 0; i < hasher._blocksize * 4; i++) {
    okey[i] ^= 0x5C
    ikey[i] ^= 0x36
  }
  var hmacbytes = hasher(util.bytesToString(okey) +
    hasher(util.bytesToString(ikey) + message, { asString: true }),
    { asBytes: true })
  return options && options.asBytes ? hmacbytes : options && options.asString ? util.bytesToString(hmacbytes) : util.bytesToHex(hmacbytes)
}

var SHA1 = Crypto.SHA1 = function (message, options) {
  var digestbytes = util.wordsToBytes(SHA1._sha1(message))
  return options && options.asBytes ? digestbytes : options && options.asString ? util.bytesToString(digestbytes) : util.bytesToHex(digestbytes)
}
SHA1._sha1 = function (message) {
  var m = util.stringToWords(message)
  var l = message.length * 8
  var w = []
  var H0 = 1732584193
  var H1 = -271733879
  var H2 = -1732584194
  var H3 = 271733878
  var H4 = -1009589776
  // Padding
  m[l >> 5] |= 0x80 << (24 - l % 32)
  m[((l + 64 >>> 9) << 4) + 15] = l
  for (var i = 0; i < m.length; i += 16) {
    var a = H0
    var b = H1
    var c = H2
    var d = H3
    var e = H4
    for (var j = 0; j < 80; j++) {
      if (j < 16) {
        w[j] = m[i + j]
      } else {
        var n = w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16]
        w[j] = (n << 1) | (n >>> 31)
      }
      var t = ((H0 << 5) | (H0 >>> 27)) + H4 + (w[j] >>> 0) + (j < 20 ? (H1 & H2 | ~H1 & H3) + 1518500249 : j < 40 ? (H1 ^ H2 ^ H3) + 1859775393 : j < 60 ? (H1 & H2 | H1 & H3 | H2 & H3) - 1894007588 : (H1 ^ H2 ^ H3) - 899497514)
      H4 = H3
      H3 = H2
      H2 = (H1 << 30) | (H1 >>> 2)
      H1 = H0
      H0 = t
    }
    H0 += a
    H1 += b
    H2 += c
    H3 += d
    H4 += e
  }
  return [H0, H1, H2, H3, H4]
}
// Package private blocksize
SHA1._blocksize = 16

export default Crypto
